Mechanism for successively producing bag lengths from continuously advancing tubularwebs



A. POTDEVIN ETAL MECHANISM FOR SUCESSIVELY PR ODUCING BAG LENGTHS FROM CONTINUOUSLY ADVANCING TUBULAR WEBS Filed Aug. 18, 1948 3 Sheets-Shget 1 SM 5 mm m W2 m m p M W mm w y 1951 A. POTDEVIN EIAL 2,560,473

MECHANISM FOR SUCESSIVELY PRODUCING BAG LENGTHS FROM CONT INUOUSLY ADVANCING TUBULAR WEBS Filed Aug 18, 1948 3 Sheets-Sheet 2 mvsnroas PO TDE I/ l N ATTORNEY ADOL PH RUDQLPH n ecu/LE rllln y 1951 A. POTDEVIN EI'AL 2,560,473

MECHANISM FOR SUCESSIVELY PRODUCING BAG u-zucms FROM CONTINUOUSLY ADVANCING TUBULAR WEBS Filed Aug. 18, 1948 3 Sheets-Sheet 3 JNVENTORS ADOLPH POTDEV/N Patented July 10, 1951 UNITED STATES PATENT OFFICE MECHANISM FOR SUCCESSIVELY PRODUC- ING BAG LENGTHS FROM CONTINUOUSLY ADVANCING TUBULAR WEBB Adolph Potdevin, Garden City,

Bechle, Yonkers, N. Y.,

Machine Company, Brooklyn,

7 tion of New York and Rudolph Paul assignors to Potdevin N. Y., a corpora- Application August 18, 1948, Serial No. 44,858 8 Claims. (Cl. 184-88) these operations taking place successively, thereby to produce bag lengths continuously.

The present invention will be described in connection with the manufacture of bag lengths for bags of the valve type. This is a well known type of bag and inherently comprises a bag length one end of which is shaped to provide a projection or lip at one corner which later is folded in to form the valve.

One object of the present invention is to provide an apparatus for the general purpose above referred to wherein the cutters for forming or shaping the leading end of the web and the cutter for severing the web back of the leading end into bag lengths move at a proper cutting speed ratio with web speed at the instant of their operation, simple means being provided for adjusting the machine to vary the length of the bag lengths produced thereon, while maintaining the proper relation between thespeed of the shaping mechanism and severing mechanism and web speed.

Other objects will appear hereinafter.

In the accompanying drawings:

Fig. 1 is a side elevatlonal view of one embodiment of the invention.

Fig. 2 is a plan view of part of the apparatus illustrated in Fig. 1;

Fig. 3 is a side elevation with some parts broken away, of the apparatus of Fig; 2.

Fig. 4 is a view similar to Fig. 2 of another embodiment of the invention;

Fig. 5 is a side elevation of Fig. 4; and

Figs. 6, 7 and 8 are isometric views of the various steps taken in the manufacture of a bag lenth from a tubular web.

Referring to the drawings in detail, and, first of all, to Figs. 1, 2, 3 and 6, '7, and 8 of the drawings:

As above explained, the present invention is directed to an improved apparatus for producing bag lengths wherein the bag lengths are cut from a tubular web, one end of the bag length being of a particular shape. For the purpose of illustration and description,- valve bag lengths have been shown on the drawings and will be specifically referred to in the specification. It is to be understood, however, that the invention comprehends the production of bag lengths other than those employed in making valve bags. in

its broadest aspect the invention is directed to mechanism for the production of bag lengths wherein one end of each length is of some particular shape but not necessarily the shape required when making conventional valve bags.

It will be appreciated that in conventional bag forming machines, means are provided for continuously advancing one or more webs of paper,

from a supply roll or rolls about folding or tubing mechanism, from whence the tubedweb passes to the mechanism constituting the subject matter of the instant invention. Inasmuch as the construction of this tubing mechanism forms no part of the present invention, and inasmuch as the same is well known in the industry, illustration and description of the same are unnecessary to a clear understanding of the invention.

As the web, which has been designated W, continuously passes from the tubingmechanism, it passes to feed rollers 2 and feed rollers 4, from whence, in the case of cement valve bags, it passes through perforating mechanism comprising segmental roller 8 and cooperating cylinder 8. The roller 8 is equipped with peripheral pins III while the cylinder 8 is equipped with corresponding depressions l2.

On continued advance of the web, its leading end is appropriately shaped by suitable mechanism, the web thereafter being severed a bag length to the rear of its leading end and the bag lengths discharged successively from the machine by a pair of discharge rollers.

The web-severing mechanism comprises an upper, positively driven rotor I 4, mounted on shaft l6 and carrying severing knife l8 extending transversely of the machine, the knife being of a length sufilcient completely to sever the widest web capable of being handled by the machine. Cooperating with the rotor I4 is lower rotor 20, mounted on shaft 22 and provided in its periphery with notch 24 which cooperates with the knife l8 as will be understood.

The web-shaping mechanism comprises an upper positively driven rotor 26 mounted on shaft 28 and ca rying a blade 30 which extends transversely of the machine and hence transversely of a web passing through the machine. The blade 30, as distinguished from the websevering knife l8 extends across the web for a portion only of the width of the web. This same rotor 26, adjacent the end of blade Ill carries the rotor and hence lengthwise of the web.

This web-shaping mechanism comprises also a lower rotor 34 mounted on shaft 88 and provided with appropriate recesses for cooperation with the blades 38 and 82.

From the brief and more or less general description thus far given, it will be appreciated that the short, circumferentially extending knife 82 when it engages the web makes a short longitudinal slit in the web along 48, Figs. 7 and 8. The transverse knife 88 then makes a transverse out along 38, Figs. '7 and 8, completely to sever the piece 42.

The discharge rollers above referred to and which are designated 44 and 48 are geared together through gears 48 and driven by belt 88 from a variable speed drive such as a Reeves drive indicated at 82.

The web-shaping mechanism and thewebsevering mechanism are driven from a main driving motor 84.

The shafts l8 and 28 carrying the web-severing rotor I4 and web-shaping rotor 28, respectively, are equipped with gears 58 and 58, in constant mesh with gears 88 and 82. These gear trains are at the front side of the machine as viewed in Fig. 3

Mounted in bearings in the side frames 84 and 88 of the machine are transversely extending shafts 88 and 18, these shafts projecting through the machine side frames and at their rear ends as viewed in Fig. 3 carrying gears I2 and 14 respectively, in constant mesh with intermediate .gear 18, driven through belt 18, from the main driving motor 84.

At the front side of the machine, as viewed in Fig. 3, we provide two housings 88 and 82 rotatably adjustable on the shafts 88 and 18 respectively. They are held in adjusted position by bolts 84 and 88 screwed into the side frame 84.

Mounted on the inside of the housing 88 is a gear 88 on stub shaft 88, this gear being in constant mesh with gear 82 aflixed to the shaft 88.

Amxed to the shaft 22 for the lower rotor 28 of the web-severing mechanism is a bifurcated crank arm 84 and cooperating with this crank arm is a crank pin 98 carried by the gear 88. Obviously by rotatably adjusting the housing 88 on the shaft 88 it is possible to adjust the eccentricity of the circular path of crank pin 98 with the path of crank arm 94, thereby imparting an aidjustable pulsating motion to rotor 28.

Mounted on the inside of the housing 82 is a gear 88 on stub shaft I88, this gear constantly meshing with gear I82 aflixed to the shaft 18.

Secured to the shaft 38 for'the lower rotor 84 of the web-shaping mechanism is a bifurcated crank arm I84, and cooperating with this crank arm is a crank pin I88. Obviously, by rotatably adjusting the housing 82 on the shaft I8 the throw of the crank arm I84 may be varied with relation to the position of rotors 28 and 84.

In the initial starting of the machine it will be appreciated that as the web W is advanced by the feed rollers 2 and 4 it comes up to the web-severing rotors I4 and 28 and is squared off across the end as illustrated at I24 in Fig. 8, the web advancing thereafter until its leading end is engaged by the web-shaping rotors 28 and 84 where a cut 48 is made at the leading and of the web, Fig. 'I, followed immediately by transverse at 8.1088 88 completely to sever strip 42 from e we As the web advances and after it enters between the overspeeded discharge rollers 44 and 48 the web-severing rotors I4 and 28 will have been rotated into severing position to sever the web a bag length to the rear of the leading end as seen in Fig. 8.

After the first bag length is cut oil, the web is first shaped at its leading end, engaged by the discharge rollers 44 and 48 and then complete- 1y severed into bag lengths. Operation is continuous.

It is to be understood that in setting the machine originally for a desired length of bag, the housing 82 is so set that at the instant the webshaping cutters engage the paper, these cutters will be moving at a desired cutting speed relative to paper speed; it is to be understood also that the housing 88 is so set that at the instant the web-severing knife engages the paper the knife will be traveling at a desired speed relative to paper speed. This adjustment and setting is possible by reason of the adjustability of the crank pins in their respective bifurcated crank arms, shifting these pins along the arms altering the speed at which the rotors will be traveling when the rotors of each pair come to operative position.

When it is desired to make a run of bag lengths either shorter or longer than the machine was originally set for, then it is merely necessary to make a change in the change gear train I I2, 4 and H8 to decrease or increase the web speed. depending upon whether shorter or longer bags are to be run. The housings 88 and 82 are then adjusted to'vary the relation of the crank pins to theirrespective cranks, whereby at the new web speed the web-shaping mechanism and the web-severing mechanism will be moving at the desired cutting speed relative to web speed when they contact the web, despite the fact that the speed of motor 54 is constant.

In other words while the rotors 28, 34 and I4. 28 are always driven at a constant number of revolutions per minute, their linear speed is not constant, and by shifting the crank pins in their respective crank arms the peripheral speed at which the rotors are traveling at the instant the two rotors of a pair are rotated into'cooperative position may be varied.

Referring to the mechanism illustrated in Figs. 4 and 5, constituting another embodiment of the invention:

In this embodiment of the invention, websevering rotors I28 and I28 and web-shaping rotors I88 and I82 are provided corresponding to similar rotors described in connection with Fig. 1. I84 and I88 designate the discharge rollers corresponding to discharge rollers 44 and 48 of Fig. 1.

The web-severing rotors are geared together one-to-one through gears I88 and I48 and the web-shaping rotors are geared together one-toone through gears I42 and I44.

The web-severing and the web-shaping rollers are driven from motor I48, belt I48, intermediate gear I88 and gears I82 and I84, the two latter gears being mounted on shafts I88 and I88 extending transversely of the machine and mounted in bearings in the machine side frames I88 and I82.

The shaft I84 for the lower rotor I28 of the web-severing mechanism projects through the side frame I82 and not only carries the gear I48 but on its extreme outer end it carries a gear I88. This gear is an elliptic gear mounted eccentrically on the shaft, see particularly Fig. 5. A similar gear I88 is mounted on the drive shaft I I6 eccentrically thereto. The eccentrically mounted gears I66 and 168 are always inmesh with each other. I

The shaft I10 for the lower rotor I32 of the web-shaping mechanism projects through the side frame I62 and not only carries the gear I but on its outer end it carries gear I12. This elliptic gear is mounted eccentrically on the shaft. see Fig. 5. A similar gear I14 is mounted on the drive shaft I58 eccentrically thereto. The eccentrically mounted gears I12 and I14 are always in meshwith each other. Inasmuch as the gears I66 and I68 and gears 6 eirecting continuous advance of the web through said cutting devices, means for varying the linear speed of the web without varying the peripheral speed of the cutting elements and means for varying the peripheral speed of the cutting elements without varying the revolutions per min- Y bination a pair of rotary cutting elements geared I12 and I'll are mounted eccentrically on their respective shafts, it will be ,appreciatedthat while the motor I46 will drive these gears and the webshaping and web-severing rotors at a constant number of revolutions per minute, the linear speed of the web-severingrotors and web-shaping rotors will not be constant throughout each revolution of the rotors.

Accordingly, for a given length of bag. the

centrically mounted gears I66, I68 and I12, I14

are reset by rotating-them on their respective shafts to alter the relation between these gears and their respective web-severing rotors and web-shaping rotors, and hence alter the peripheral speed of these rotors at the instant the rotors of each pair are rotated into cooperative relation, so that at that instant, the rotors will be traveling at the proper peripheral cutting speed relative to the new web speed.

From all of the foregoing, it will be seen that we have provided a web handling machine wherein the leading end of the web is always shaped in advance of cutting or severing the web for a bag length. It will be apparent also that very simple mechanism has been provided for adjusting the web-shaping mechanism and the websevering mechanism in accordance with variations in web speed when changing bag lengths with the assurance that each of these mechanisms will engage the web at proper cutting speed ratio to web speed so that tearing of the web or plugging of the machine are avoided.

It is to be understood that changes may be made in the details of construction and arrangement of parts herein described and illustrated within the purview of my invention.

What we claim is:

1. Web cutting mechanism comprising 'in combination a pair of rotary cutting elements adapted to receive the leading end'of a continuously advancing web between them and to impart a predetermined shape to the web end, a. second pair of rotary cutting elements to the rear of the first pair and adapted to receive the continuously advancing web between them and arranged completely to sever the web to the rear of the shaped leading end after the completion of the shaping of the leading end, means for rotating said cutting elements at a fixed number of revolutions per minute, rotatable means for to each other and adapted to receive the leading endor a continuously advancing web between them and to impart a predetermined shape to the web end, a second pair of rotary cutting elements to the rear of the first pair and adapted to receive the continuously advancing web between them and arrange i completely to sever the web to the rear of the leading end after the leading end has been completely shaped, gearing arranged to drive each pair of cutting elements at a fixed number of revolutions per minute but at non-uniform peripheralspeed, and means for varying the setting of said gearing to vary the peripheral speed at which the cutting elements are moving when brought into engagement with the traveling web whereby the cutting elements will be moving at a predetermined peripheral speed relationship to web speed under all conditions of web speed. at the instant of operation of the cutting elements.

3. Web-cutting mechanism comprising in combination a pair of feed rollers for continuously advancing a web, means for varying the speed of said rollers thereby to vary the linear speed of the web, a pair of rotatable cutting elements geared together, and adapted to receive the leading end of the web between them, said elements when rotated into cooperative relation to each other shaping the leading end of the web to a predetermined shape, a second pair of rotatable cutting elements intermediate the first men-- tioned cutting elements and the feed rollers,

the last mentioned cutting elements being geared together and adapted when rotated into cooperative relation completely to sever the web to the rear of its leading end after the leading end has been completely shaped, gear trains for the cutting elements for rotating the same at a constant number of revolutions per minute, and means for adjusting said gear trains so as to vary the peripheral speed of the cutting elements as they are brought into cooperative relation to conform to variations in the linear speed of the web without altering the revolutions per minute of the cutting elements.

4. Web cutting mechanism comprising in combination a pair of feed rollers for continuously advancing a web, change speed gearing for varying the linear speed of the web, a pair of rotatable cutting elements geared together, in the path of the advancing web, and adapted when rotated into cooperative relation to impart a predetermined shape to the leading end of the web, a second pair of rotatable cutting elements intermediate the first pair of said feed rollers, said last mentioned cutting elements being geared together and adapted when rotated into cooperative relation completely to sever the web to the rear of its leading end after the leading end has been completely shaped, gear trains for the cutting elements, each comprising a gear rotated at a fixed number of revolutions per minute and connected to one of the gears of the cutting elements through an adjustable crank arm and crank pin, whereby the peripheral speed of the cutting elements when brought into cooperative relation may be varied, without altering the revolutions per minute of the cutting elements, to accommodate the mechanism to variations in the linear speed of the web.

5. Web-cutting mechanism comprising, in combination, rotatable, intermittently operating webshaping mechanism adapted to receive the leading end of a continuously advancing web and impart a predetermined shape to the web end. a rotatable, intermittently operating web-severing mechanism to the rear of the web-shaping mechanism adapted completely to-sever the web to the rear of the leading end after the completion of the shaping of the leading end, means for rotating said web-shaping mechanism and said websevering mechanism at a fixed number of revolutions per minute, rotatable means for effecting continuous advance of the web, means for varying the linear speed of the web wtihout varying the peripheral speed of the web-shaping and websevering mechanisms, and means for varying the peripheral speed of the web-shaping and websevering mechanisms without varying their revolutions per minute, whereby the severed web sections may be varied in length, the web-shaping and web-severing mechanisms, when contacting the web, traveling at a predetermined peripheral speed relationship to the linear speed of the web.

6. Web-cutting mechanism comprising, in combination, rotatable means for continuously advancing the web, rotatable, intermittently operating shaping mechanism for shaping the leading end of the continuously advancing web, rotatable web-severing mechanism intermediate the webadvancing means and the web-shaping mechanism arranged completely to sever the web to the rear of the leading end after the, completion of the shaping of the leading end, means for varying the speed of rotation of the web-advancing means to vary the linear speed of the web without varying the peripheral speed of the web-shaping and web-severing mechanisms, means for varying the peripheral speed of the web-shaping and websevering mechanisms without varying their revolutions per minute, whereby the length'of the severed sections may be varied, the web-shaping and web-severing mechanisms traveling at a predetermined peripheral speed relationship to the linear speed oi the web when contacting the web.

7. Web-cutting mechanism comprising, in combination, web-advancing means for continuously advancing the web, intermittently operating webshaping mechanism for shaping the leading end of the web, intermittently operating mechanism intermediate the web-advancing means and the web-shaping mechanism for completely severing the web to the rear of its leading end, means for varying the linear speed oi the web without varying the peripheral speed of the web-shaping and web-severing mechanisms, means for varying the peripheral speed of the web-shaping and websevering mechanisms to vary the length of the severed sections, the web-shaping and web-severing mechanisms moving at a predetermined speed relationship to the linear speed of the web when contacting the web.

8. Web-cutting mechanism comprising, in combination, a pair of rotary cutting elements geared to each other and adapted to receive the leading end of a continuously advancing web between them and to impart a predetermined shape to the web end, a second pair of rotary cutting elements to the rear of the first pair and adapted to receive the continuously advancing web between .them and arranged completely to sever the web REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 873,341 Barber Dec. 10, 1907 1,542,104 Smith June 16, 1925 1,975,123 Potdevin Oct. 2, 1934 OTHER REFERENCES Overbury Reissue, 15,328, Apr. 4, 1922. 

